1. Field of the Invention
The present invention relates to a transporting apparatus for transporting a transported object, for example, various substrates and the like for manufacturing semiconductor devices, on a track portion, a transporting system including the transporting apparatus and the track portion, and an elongation mechanism used for the transporting apparatus. Here, the “transported object” means a product, an intermediate product, a part, an article, a work, a partly-finished good, a good or the like, or means a box or container for containing such a product or the like, which has been transported or is to be transported by the apparatus.
2. Description of the Related Art
As this type of transporting apparatus, there is a transporting apparatus of an OHT (Overhead Hoist Transport) type, which travels on the track portion, installed on or near the ceiling. Moreover, there is a transporting apparatus that can transfer or load a transported object, placed except under the track portion, i.e. placed on the side of the track portion (hereinafter referred to as “lateral transfer”, as occasion demands).
For example, Japanese Patent Application Laying Open NO. Hei 11-180505 discloses a technology which allows the lateral transfer by providing a transferring device, which can move on a horizontal surface, in the lower portion of a transporting carriage. Moreover, Japanese Patent Application Laying Open NO. 2005-206371 discloses a technology which allows the lateral transfer by providing a ceiling buffer on the lateral side of the transporting carriage and by displacing a lift to the ceiling buffer. Furthermore, Japanese Patent Application Laying Open NO. 2006-282303 discloses a technology which allows the lateral transfer by providing an object placing stage on the lateral side of the track.
The transporting apparatus, disclosed in the patent documents, is provided with an elongation mechanism for laterally elongating a loading device, mechanically, using a gear, rack, pinion, motor, and the like, when performing the lateral transfer.
However, there is such a technical problem that it is technically hard to make the elongation mechanism, which is to perform the lateral transfer as described above, extendable with a sufficient length and sufficient strength at the time of elongation, while making the mechanism small enough not to interfere with the travel of the transporting apparatus at the time of non-elongation.